Removal of Heavy Metals Using Fish Scales

The selection of activated carbon has always preceded other adsorbents as the
material is the most versatile adsorbent in industry. However, the trend nowadays is
aimed at diversifying the origin of adsorbent most of which comes from micro
organisms and biomass product. This project is aimed to study the feasibility of
using fish scale as industrial adsorbent to remove heavy metal from its aqueous
solution. The adsorptive nature of three types of metals namely Copper (Cu), Nickel
(Ni) and Lead (Pb) on fish scale are studied independently.
These objectives were achieved via batch experiment whereby a set of metal
solution is added with the fish scales and the adsorption test was carried out. The
fish scales were first washed with deionized water and further grinded into
powdered form (<500um). Fish scales activation was not implemented inthis study.
The effects of initial metal concentration and temperature were studied in the
adsorption test. The effect of initial metal concentration was studied at lOppm,
30ppm and 50ppm while the effect oftemperature was studied at 20°C, 30°C, 40°C
and 50°C. Atomic Absorption Spectrophotometer (A.A.S) was usedto determine the
concentration of the identified metal in the particular solution. Fourier Transform
Infrared Spectrophotometer (FTIR) was used to determine the functional group of
the fish scales.
Batch experiments and isotherm kinetics studies were carried out to
investigate the effect of contact time, initial concentration of the adsorbate, particle
size and temperature. It was noted that an increase in the metal concentration and
temperature and a reduction in particle size resulted in an increase in the metal
uptake per unit weight of adsorbent. For temperature effect, however the trend
increases up to a maximum temperature then decreases. The maximum temperature
depends on the type ofheavymetal and they differ from one another.
Langmuir and Freundlich adsorption isotherms were applied to calculatethe
thermodynamics properties of the adsorption process. The feasibility and
IV spontaneous nature of adsorption process is well confirmed from thenegative values
of -AG0 The positive values of enthalpy change (AH°) further suggest the
endothermic nature, while positive AS0 values reflect the affinity of the adsorbent
materials towards lead and also as an indication that the disorder of the adsorption
process increases. The FTIR analysis showed that there are a lot of functional group
that exist on the surface of the fish scales; hydroxyl, carbonyl, carboxyl, amides,
amines, and esters.